Recent advances in sensor, electronics, and power source miniaturization have allowed the size of personal health monitoring devices, also referred to herein as “biometric tracking” or “biometric monitoring” devices, to be offered in small sizes. These biometric monitoring devices may collect, derive, and/or provide one or more of the following types of information: heart rate, calorie burn, floors climbed and/or descended, location and/or heading, elevation, ambulatory speed and/or distance traveled, etc. One piece of useful physiological information measured by biometric monitoring devices relates to heart rate. As biometric monitoring devices are trending to integrate multiple sensors to measure various types of physiological and environmental information, existing devices that measure momentary heart rate require cumbersome user interaction to take the measurement, display the measured information and/or provide other user feedback. This disclosure provides biometric monitoring devices with convenient and user-friendly heart rate monitoring function.